SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3a8dae05e9a1296a8bb77b0ce9eca1bce0ac9cb186b07b133047d2a2576a942' 
  AND token = 'kuoHMNSVcqUxtbrlD/7IJ18GDPK6B3pGD1aHQdrSBVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}